Most diets are efficient in short-term weight reduction due to caloric restriction, but 80% of people regain all lost weight within 12 months.

“So that person diets on one of these many diets, loses weight back to his or her original low body weight, but then within 12 months of successfully dieting, 80% of people go on to redevelop obesity or regain all the weight that they've lost and even regain a little bit more than they originally had.”